The socioeconomic impact of Alzheimer’s disease (AD) and dementia is enormous worldwide and poses considerable challenges in the management and prevention of these debilitating states. An international team from 5 countries has created a new framework for AD and measuring its long-term economic impact on individuals and society (Wimo A, et al. J Intern Med. 2014;275: 304-316).
The investigators posit that the 4 main priorities for cost-effectiveness studies in AD should include (1) determining the consequences to healthcare systems if the diagnosis of predementia states rather than clinical dementia become the main focus, (2) filling in the gaps between data from clinical trials and patients treated in the real-world setting, (3) translating clinical trial end points into measures that are meaningful to all stakeholders, and (4) accurately measuring the long-term effects of dementia on individuals and on society.
“To improve cost-effectiveness studies, long-term population-based data on disease progression, costs and outcomes in clinical practice are needed not only in dementia but also in predementia states,” wrote Anders Wimo, MD, PhD, Adjunct Professor, Karolinska Institutet Alzheimer’s Disease Research Center, Department of Neurobiology, Care Sciences and Society, Stockholm, Sweden, and other AD experts from Sweden, Holland, the United Kingdom, Slovenia, and Canada.
Their starting point was the diagnostic criteria for preclinical AD written by members of the National Institute on Aging and the Alzheimer’s Association workgroups (McKhann GM, et al. Alzheimers Dement. 2011;7: 263-269). Clinical examination, neuropsychological examination, positron emission tomography, magnetic resonance imaging, and the analysis of cerebrospinal fluid have key roles to play in diagnosing mild cognitive impairment and AD.
The team noted that an optimal diagnostic pathway has not yet been identified, and that new tools also add new dimensions and new costs to possible pathways.
The experts also concluded that there are major challenges to determining the cost-effectiveness of diagnosing preclinical AD versus mild cognitive impairment versus dementia. Even if it becomes possible in the future to calculate the costs for diagnosing these earlier stages of disease, the complication is determining the consequences, and hence costs, of living with a false-positive diagnosis for several years.
Disease-Modifying Therapies Key to Future Success?
“Is this situation unique for AD? Perhaps not, but a shift in the diagnostic spectrum from AD-dementia to predementia states will probably make the risk of FPs [false-positives] greater, because the diagnosis of AD is not straightforward,” stated Dr Wimo and colleagues. In the current absence of effective disease-modifying therapies for patients with AD, “any screening programme for AD generally is problematic and hardly recommendable,” they noted.
However, if and when disease-modifying treatments are available for this condition, diagnostic protocols with accompanying cost-effective analyses could be fleshed out. The first step would likely be screening at the primary care level, followed by confirmation of the diagnosis and the creation of a management approach at the specialist level.
Dr Wimo and colleagues considered the possible consequences of bringing predementia into the dementia-diagnosis tent. “We are now facing a new challenge in the management and diagnosis of AD. Many trials have failed, but there are still several DMT [disease-modifying treatments] approaches in the pipeline,” they noted, adding that if effective disease-modifying treatments do become available, “the magnitude of the potential target population will be large, and there will be a high demand for diagnosis and care.”
Furthermore, a new type of infrastructure for early diagnosis would need to be established, the team noted, and if and when new disease-modifying treatments are developed, “it is also important to identify the most cost-effective diagnostic pathway at the specialist level (the optimum number and most effective sequence of tests),” wrote Dr Wimo and colleagues.
The team also pointed out the potential pitfall in which scarce resources may be shifted from severe-dementia care to focus on patients with early AD, in which case “we need to have good instruments for cost-effectiveness analyses as a support in decision-making,” noted Dr Wimo and colleagues. “Modelling the cost-effectiveness of interventions in the predementia stages of AD requires longitudinal data on progression through the disease stages, resource utilization and quality of life, all of which are rarely available at present.”
Furthermore, they noted, more work is needed on translating clinical trial end points into entities that can be integrated into daily practice and policymaking, and for more data on long-term outcomes and mortality.
They pointed out that trials to date have been “too short to show effects on mortality and selection bias was present in trials (younger and more healthy).” Evaluations of economic effects on mortality “will need to combine short-term clinical trial data with long-term disease progression through a disease-modelling framework,” Dr Wimo and colleagues concluded.